In the related art, when a semiconductor element such as a vertical power device is formed using a SiC substrate, in order to reduce a substrate resistance, it has been checked grinding a rear surface side of the SiC substrate to make a thin plate, after various impurity layers or electrodes which form the device are formed on a front surface side. In this case, there is a need to form an ohmic electrode on the rear surface side, after grinding the rear surface side of the SiC substrate. However, when the ohmic electrode is formed, various impurity layers or electrodes which form the device are already provided on the front surface side of the SiC substrate. Thus, there is a need to set a configuration such that thermal damage is not applied to the impurity layers or the electrodes. For example, as a technology for not applying the thermal damage, a laser annealing technology which is capable of performing local heating is used.
When the ohmic electrode is formed using the laser annealing or the like, for example, nickel (Ni) or the like is used as an electrode material, and silicide is made by performing a bonding with Si which is included in the SiC to obtain an ohmic connection. On the other hand, C which is included in the SiC precipitates as a graphite at an interface between the ohmic electrode and the SiC. Therefore, generation of the graphite is prevented, using a metal such as molybdenum (Mo) which makes carbide, in addition to the electrode material for forming the ohmic electrode (see Patent Literature 1).